The present invention relates to a method and apparatus for electrically controlling a central locking system and a securing device for motor vehicles which have at least one lock cylinder with at least two associated control switches. For the electrical control of the unlocking or locking of the central locking system and the disabling or enabling of the securing device, the lock cylinder is pivotable by means of a key out of a neutral position in an unlocking direction or oppositely in a locking direction and at least beyond a regular locking position by further pivoting in the locking direction into a securing position for enabling the securing device. A securing device is provided for additional mechanical blocking of locked closures that is enabled and disabled by means of signals generated by the two control switches.
A central locking system and securing device of the above type is known from German Patent Document DE 3,513,555 C2. To control an additional securing or blocking device for the actuating elements of a central locking system by means of a lock cylinder, there is a first microswitch for enabling and a second microswitch for disabling the blocking of the actuating-element assigned to the lock cylinder. In a known way, this blocking mechanically prevents a secured vehicle from being opened from inside after a window pane has been knocked out. A third microswitch is assigned to the lock cylinder for controlling the central locking system, although this control itself is not described in more detail in the above-referenced Patent Document.
A lockable actuating element which can be used in a device of the relevant generic type is known from German Patent Document DE 3,804,838 C1. In particular, even when the additional safeguard is enabled, this actuating element makes it possible to carry out the purely mechanical release of the closure assigned to it and consequently to use the vehicle even in the event of a possible failure of the vehicle battery voltage necessary for disabling the securing device.
In modern motor vehicle construction, the lock cylinders of the mechanical closing system are allowed less and less constructional space in the doors. This results in proposals for shifting control microswitches out of the immediate vicinity of the lock cylinder towards a follower rotationally coupled to the lock cylinder. (German Patent Documents DE 3,717,778 A1, DE 3,827,564 C1).
With this in view, both lock cylinder constructions mentioned immediately above involve a high outlay and a number of electrical control switches. It is known from German Patent Document DE 3,307,542 C2 to control both a central locking system and an additional theft security system by means of an axially split lock cylinder, two electrical control switches being switched simultaneously in the lock cylinder when a special security key is used. In this reference, the two control switches are designed as bistable change-over switches, each with three terminals, and one of the switches is intended solely for controlling the central locking system and the other solely for controlling the theft security system. Moreover, there also has to be a priority control involving a high outlay which ensures the correct time sequence of the individual locking operations (that is to say, first "lock" and then "secure" or first "desecure" and then "unlock").
Finally, it is known from German Patent Document DE 3,516,732 C1 to control a burglar/anti-theft warning system in a motor vehicle via a control switch of the central locking system of the vehicle. When a master key or security key is used in the lock cylinder, a lock-cylinder switch activates a switching device which also causes switch signals of the control switch to be fed to the control unit of the burglar/anti-theft warning system.
An object of the invention is to provide a process by which, with the operating sequence being constant, there is a better utilization of existing electrical switching means of a locking and securing device. It is also an object to provide for the electrical control of a locking and securing device for motor vehicles in such a way that, while the simple switch design is preserved, it is possible, with a constant operating sequence, to use fewer electrical switches.
This and other objects are achieved by the present invention which provides a method for electrically controlling a central locking system and a securing device for motor vehicles which have at least one lock cylinder with at least two associated control switches. For the electrical control of the unlocking or locking of the central locking system and the disabling or enabling of the securing device, the lock cylinder is pivotable by means of a key out of a neutral position in an unlocking direction or oppositely in a locking direction and at least beyond a regular locking position by further pivoting in the locking direction into a securing position for enabling the securing device. A securing device is provided for additional mechanical blocking of locked closures that is enabled and disabled by means of signals generated by the two control switches. The method of the present invention comprises the steps of controlling the central locking system in the unlocking or locking directions by actuating one of the associated control switches, and successively actuating the two control switches during the pivoting of the lock cylinder into the securing position and simultaneously switching the two control switches into a joint switching state immediately following the successive actuation of the two control switches during the pivoting of the lock cylinder into the securing position. The joint switching state for enabling the securing device is evaluated and the securing device is disabled by actuating the control switch that is actuated during the pivoting of the lock cylinder in the unlocking direction.
By means of two simple touch-contact switches, at least three different positive signal states, that are distinguishable from the non-actuated state of rest without setting at a specific electrical potential, can be produced. These signal states are: 1) first switch closed, second switch open; 2) first switch open, second switch closed; and 3) both switches closed at the same time.
The switching states of the two switches can in each case be evaluated both individually and jointly in AND operation.
According to the invention, state 3) is obtained in that, during the further pivoting of the lock cylinder beyond the regular locking position into a securing position in which the locking control switch is closed, the unlocking control switch is also additionally closed. State 3) can also be obtained in that, during the further pivoting of the lock cylinder beyond the regular unlocking position into a desecuring position in which the unlocking control switch is closed, the locking control switch is also additionally closed.
In an embodiment of the present invention, the central locking system is controlled in the unlocking and the locking direction by means of the switching states 1) and 2) respectively, and the securing device is connected by means of the switching state 3). In this procedure, the sequence "first lock, then secure" is also directly maintained, because by means of the individual signal from the locking control switch the central locking system is already activated in the locking direction, and only thereafter, when the simultaneous activation of the unlocking control switch occurs, can the securing device be activated in the securing direction. There is no need in this case for a special "desecuring position", because, in a manner known per se (German Patent Document DE 3,334,049 C2), the securing device can be disconnected again by a simple "unlock" control signal from the unlocking control switch (with the rotation of the key in the unlocking direction). Here too, of course, internal signal processing guarantees the necessary priority.
It is known from German Patent Document DE 3,703,590 C1 to control a central locking system by means of simple touch-contact change-over devices with a middle position, the same electrical potential being applicable to two different inputs (locking and unlocking input) of a control unit by means of the touch-contact change-over devices. In principle, the touch-contact change-over devices used there could each be replaced in an equivalent manner by two individual touch-contact switches, but the above-mentioned patent document gives no indication as to the simultaneous actuation of the two touch-contact switches which are provided per se for activating a central locking system in different operating directions for the control of a mechanical securing device.
In another embodiment of the method of the present invention, the switching state 3), in which the two control switches are actuated simultaneously after switching, is advantageously evaluated for generating different switching effects by taking into account the switching sequence of the control switches. With simple electrical or electronic switching means, it is possible to enable the mechanical securing device if the control switch used for the locking control is actuated first and then the control switch used for the unlocking control and both also remain actuated at the same time. To this extent, the arrangement corresponds to that already described. Conversely, however, the mechanical securing device can be disabled only when the control switch used for the unlocking control is actuated first and then the control switch used for the locking control and both also remain actuated at the same time.
In this case, of course, the time sequence "first desecure, then unlock" is ensured again, and this can be obtained, for example, in that, when the securing device is connected, a simple unlocking control signal from the unlocking control switch is not processed as a result of electrical suppression. The particular switching state of the securing device can directly, in a known manner, be stored in a central control unit and called up.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.